Deputy Prime Minister Didier Reynders urged Mr Leterme to stay on and push through the government's social and economic policies.

Belgium's Dutch and French-speaking communities seem to exist side-by-side, but with little interaction, says the BBC's Dominic Hughes in Brussels.

No single party bridges the linguistic and geographic gulf between Belgium's two regions though, traditionally, the prime minister comes from one of the majority Flemish parties.

Hardline nationalist parties, including the Flemish Interest Party, are advocating the division of the country.

Its parliamentary leader Gerolf Annemans said Flemish parties should move towards an independent Flanders by "not just pulling the little plug on the government, but the big one," referring to Belgium.

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